Columbia University’s main lawn continued to be a central focus on Monday of antiwar protests that are spreading across U.S. universities, as student protesters resumed their largely peaceful campout despite the arrests of more than 100 people on the school’s Morningside Heights campus last week.

But the scene outside the storied university’s iron gates turned rowdy at points, as outside protesters gathered to support or oppose the students rallying on behalf of the Palestinian victims of the Israel-Hamas war, and as members of the media, law enforcement and government converged to monitor the events around the usually tranquil campus.

Columbia’s administration overnight ordered all classes to be held remotely on Monday, a rare move that came amid increasing tensions over events on and near the campus and a national spotlight on the Ivy League university.

The frenzy followed a rancorous week in which pro-Palestinian students occupied tents on the school’s main lawn in protest of the war and what they said were Columbia’s investments in Israel. Over 100 people were arrested on Thursday after the administration called in the NYPD following congressional testimony by Columbia’s president, and some students were suspended. And over the weekend, antisemitic incidents on and near the campus drew quick condemnation from the White House, New York City Mayor Eric Adams and others ahead of the weeklong Jewish holiday of Passover, which begins on Monday evening.

The commotion was among similar events playing out at universities along the East Coast, including NYU’s downtown campus and Yale’s New Haven campus, where dozens of students were arrested on Monday. New York Gov. Kathy Hochul showed up at Columbia’s campus on Monday morning, saying she had met with university and city officials “to discuss the need to fight antisemitism and protect public safety.”

NYPD officials said late Monday morning there were no credible threats of physical violence connected to the ongoing protests in New York City. Adams on Sunday had sounded the alarm about reports of antisemitic hate speech at Columbia and urged the school’s leadership to “improve and maintain an open line of communication with the NYPD.”

The scene outside Columbia’s gates appeared generally more raucous than that within. On Columbia’s main lawn where pro-Palestinian demonstrators set up their encampment, people listened to lectures while sitting on the grass, shared meals and drinks and did yoga and stretches. Immediately outside, protesters on different sides of the conflict in Gaza chanted loudly, waved flags and signs, and occasionally confronted each other.

Despite general concerns of unrest, students in the Columbia University Apartheid Divest Coalition who are occupying the school’s main lawn have taken pains to conduct themselves carefully. Each person who entered the space had to agree to a set of behavioral guidelines, including respecting others’ personal space and not taking photography without consent. A poster displayed near the tents outlined a schedule of events for the day.

Two people were arrested outside the school’s grounds on Monday on charges of disorderly conduct, according to the NYPD.

On Monday afternoon, more than a hundred professors from Columbia and Barnard College, which is affiliated with the university, demonstrated in support of the student protesters in the encampment. Standing outside the Low Memorial Library off Columbia’s main lawn, the professors — some of whom were wearing ceremonial robes — held signs stating “hands off our students” and “end students’ suspensions now.”

Several professors took the mic to lambast the actions of University President Minouche Shafikand called for students’ disciplinary records to be expunged.

“The president’s decision to send riot police to pick up peaceful protesters on our campus was unprecedented, unjustified, disproportionate, divisive and dangerous,” said Christopher Brown, a history professor, referring to last Thursday’s events.

His statements were followed by roaring applause from students, who began chanting “resign, resign, resign!”

Just outside the campus gates, Iris Hsiang said she was one of the people arrested last week for alleged trespassing after school officials asked the NYPD to clear an encampment of tents and sleeping bags where protestors had slept overnight. The Columbia sophomore said she’s now suspended and has received a court summons.

“There are no universities standing in Gaza right now,” Hsiang said. “There is a genocide occuring and this university is invested in it.”

Swaths of police officers surrounded the campus throughout the day, barricading entrances to the university grounds as police drones and helicopters patrolled the skies. Members of the NYPD’s Strategic Response Group — a heavily armored unit created in 2015 to combat domestic terrorism and respond to protests — stood in formation along Broadway throughout the morning and early afternoon.

Police cannot legally enter Columbia’s private property unless university officials request it — as happened last Thursday — said Michael Gerber, the NYPD’s deputy commissioner of legal matters, at a news conference just outside of the campus. “Absent some ongoing crime, we cannot just go onto Columbia campus as we see fit,” he said. “It is up to the university.”

Students interviewed at the encampment said they were there to peacefully protest the university over its financial ties to Israel. Mohsen Mahdawi, who has participated in the encampment with his peers for more than five days, said it posed no risk or danger to his fellow students.

“We are transparent, there is nothing to hide,” Madawi said. “And we tell the whole world here to come watch us walk in the encampment and see that this is a protest that is peaceful and that is calling for two principles: the principle of equal human rights for all and the principle of free speech.”

The demonstrators said they took inspiration from a historic protest on Columbia’s campus in 1968, when students occupied several university buildings to protest the U.S.’s involvement in the Vietnam War.

Shafik, the school’s president, announced in the early morning hours on Monday that classes would be held remotely to “deescalate the rancor and give us all a chance to consider next steps.” She said university officials hoped students who lived off campus would remain there and that staff who could work remotely would do so.

Shaya Shwarz, a freshman at Columbia, said his classes and exams were postponed due to the shift to virtual learning. Schwarz, who is Jewish, said he was headed home to Los Angeles that day for Passover at the insistence of his parents, who worried about his safety after watching the news.

Schwarz said most of the pro-Palestinian protests on campus have been peaceful, but added that he was unnerved with one incident where another Jewish classmate was approached by students who attempted to burn the Israeli flag he was carrying..

“A large majority of the Jewish students are going home because they don’t feel comfortable on campus,” he said. “It’s pretty crazy, we are literally the headlines of every single news station.”

This is a developing story and may be updated.